A container generally comprises an open neck, through which the contents (ordinarily a liquid) are introduced and through which the contents are emptied, a body, which imparts to the container its volume, and a bottom, which closes the body opposite the neck and forms a base intended to ensure the stability and the holding of the container when it rests on a support such as a table.
Containers are known that are provided with petal-shaped bottoms, which comprise projecting feet, in the shape of petals, separated by convex wall portions, called hollows or valleys, which extend radially from a central zone of the bottom. The feet are intended to ensure the stable holding of the container on a support; the valleys are intended to absorb the forces (thermal and/or mechanical) exerted by the contents.
The large-height petal-shaped bottoms (i.e., whose feet have a height in a ratio with the diameter of the container that is greater than or equal to ½) exhibit a high mechanical strength; this makes them particularly suitable for carbonated liquids (in other words, for carbonated beverages) that generate pressures of more than 2.5 bars. An illustrative example of this type of bottom will be found in the international application WO 2012/069759 (SIDEL).
However, the petal-shaped bottoms of this type consume a considerable amount of material (a 0.5 l container with a standard petal-shaped bottom has a weight on the order of—or greater than—approximately 18 g).
An attempt has been made to adapt the petal-shaped bottoms to flat liquids (for example, plain water) or slightly carbonated liquids (generating an internal pressure that is less than or equal to 2.5 bars), or else to slightly pressurized liquids (on the order of 0.3 bar to 1 bar) by means of a neutral gas (such as nitrogen). To limit the amount of material necessary for the manufacturing of a petal-shaped bottom, the height of the bottom has been reduced, and the bottom has been reinforced, in the valleys, by means of grooves overlapping a central dome. This technique, illustrated in the international application WO 2014/207331 (SIDEL), proved itself and made it possible to reduce the quantity of material to approximately 10 g for a container with a 0.5 l capacity. However, constraints with regard to conserving material are steadily tightening, and today manufacturers are being asked to reduce the weight of the containers by an additional 10 to 20% (or weight on the order of 8 g to 9 g for a container with a 0.5 l capacity).
Under these conditions, the known shapes cease to be pertinent and new solutions should be found to maintain or to increase, at reduced weight, the rigidity of the bottoms of the containers.
In particular, it was noted that by lightening by 15% the petal-shaped bottom of the type described in the above-cited application WO 2014/207331, this bottom deforms under an internal pressure that is greater than or equal to 0.5 bar. More specifically, folds appear in an uncontrolled manner in the valleys, which weakens the bottom of the container and makes its stacking (and therefore its palletization) hazardous.